Blue-light-emitting complexes: Cationic (2-phenylpyridinato)iridium(III) complexes with strong-field ancillary ligands

The emission) lambda(max) are strikingly shorter (451, 482 nm) for the cationic dicarbonyl complex [Ir(ppy)(2)(CO)(2)](+) (2a) than those (473, 495 nm) of the anionic dicyano complex [Ir(ppy)(2)(-)(CN)(2)](-), where CO and CN- are both sp carbon coordinating ligands and known to be strong-field ligands showing a high trans effect. Sky-blue-light emission (lambda(max) = 441-443 and 470-471 nm) could be obtained by modifying the ppy ligand to F(2)Meppy (2,4-difluoro-2-phenyl-m-methylpyridinato anion) to prepare [Ir(F(2)Meppy)(2)LL'](+) [LL'=(CO)(2) (2aF(2)Me), (PPh2Me)(2) (2bF(2)Me)]. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).